This invention relates to ramps for loading and unloading trucks, trailers and vans, specifically to those ramps that pivot and telescope.
Over the years many systems have been developed in an effort to efficiently load items on and unload them off the cargo beds of trucks, trailers and vans. There have been various types of mechanical lifts, ramps, loading docks and other devices.
Trucks with ramps that tilt and telescope to the ground have been the most successful in fulfilling this job, however, most of these are attached directly to the vehicle""s frame rather than on a cargo bed. U.S. Pat. 3,550,801 to Larson (1970) discloses a design that connects the ramp components to the framework of a truck that has no stationary cargo bed. U.S. Pat. 3,768,673 to Nydam et al (1973) discloses a system of limited capability. It is not powered in either its telescopic or pivoting functions. Their system shows the tailgate hinged in a downward position which is not possible with current tailgate design since the bumper would be in the way. U.S. Pat. No. 5,603,600 to Egan et al (1997) has elevated his system so that it will reside above a closed tailgate. Since the pivoting is not controlled while loading or unloading their system must be limited to light loads an operator can handle while at the same time working the winch.
Several of the many objects and advantages of the present invention are:
(1) to provide a ramp which will reside on the cargo bed of a truck, trailer or van rather than being attached to the vehicle""s frame and without major alterations to the cargo bed;
(2) to provide a ramp which will be primarily self contained and can be marketed as an easy to install package;
(3) to provide a ramp which will have most of its components installed within and above the cargo bed rather than under it;
(4) to provide a ramp which will have a minimum height so as to not consume a large volume of the cargo compartment;
(5) to provide a ramp which will have a gradual incline when pivoted down and extended to the ground;
(6) to provide a ramp for a pickup truck which will allow for a modified tailgate to be located in its normal location while allowing for the ramp to reside and telescope underneath;
(7) to provide a ramp for vehicles having wheel wells that allow for the main longitudinal structural members to reside between the wheel wells;
(8) to provide a ramp for a pickup truck which will allow for the main longitudinal structural members to reside between the wheel wells, but for the portion aft of the wheel wells to extend to almost the width of the tailgate, and aft of the tailgate to extend to any desired width;
(9) to provide a ramp which will allow for its top surface to be a combination of conventional conveyor devices and stationary deck materials;
(10) to provide a ramp which may have a powered pulling system for loading as well as a powered pushing system for unloading.
Further objects and advantages are to provide a ramp system that will allow an operator to still use those areas of the cargo bed not occupied by the ramp, and since the cargo bed is still intact small items that may fall from a retracted ramp will fall on the cargo bed rather than onto the ground. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.